In medical work, medical personnel are exposed to substances with biological hazards for a long time. For the health of oneself and patients, reduce iatrogenic infection. Safety first? Is a principle that must be observed. The following is the knowledge I brought to you about the safety of blood testing for medical staff. Welcome to reading.
First, the risk of HBV and HIV in hematological tests Many viral infectious diseases are spread through blood, among which HBV and HIV pose the greatest threat to medical staff. The infection routes of HIV and HBV are similar, and medical staff may be infected when they come into contact with HIV or HBV positive blood samples. However, the concentration of HBV in blood can be as high as 108 ~ 109/ml, and the concentration of hepatitis C virus (HCV) in blood is about 102 ~ 103/ml, while HIV is usually only100 ~/kl. The number of occupational HBV infection among medical staff is far more than that of AIDS infection. Although HBV and HIV also exist in saliva, tears and other secretions, blood-borne HBV and HIV infections account for the vast majority of occupational HBV and HIV infections among medical staff.
Since the first case of AIDS was discovered in 198 1, it has attracted wide attention and even caused panic in a certain range because of its serious biological and sociological consequences. However, research shows that the viability of HIV in the environment is much lower than that of HBV. At 25℃, HBV can remain active in blood products or dried blood clots for more than 7 days, but HIV is easily destroyed. Studies have shown that air drying can make the HIV infection activity decrease exponentially in a short time, and it can decrease by 90% ~ 99% in a few hours. It has been reported that at room temperature (23 ~ 27℃), 90% of HIV is inactivated every 9 hours. For preventive measures, the existing conventional cleaning, disinfection and sterilization methods that are effective for HIV and HBV are completely effective, so there is no need to panic.
The transmission of HBV and HIV in the laboratory can be roughly divided into direct contact and indirect contact.
There are three ways of direct contact:
(1) Puncture: The whole blood, serum or plasma with virus enters the subcutaneous or circulatory system due to accidental skin injury caused by needles and blades, resulting in infection. This accidental needle injury is the most important cause of occupational HBV and HIV infection. After a needle with HIV accidentally punctures the skin, the probability of HIV infection is between 0% and 0.9%, with an average of 0.4%, while for HBV, the probability is between 6% and 30%, with an average of 18%. Some scholars have made corresponding statistical calculations, and every 1000 AIDS patients will produce 1 case of occupational HIV infection caused by needle accidents every year; For every 1000 hepatitis B patients, 45 cases of similar occupational HBV infection will occur every year. Because the infection rate of HBV in the population is much higher than that of HIV, in a certain population, the occupational HBV infection caused by needle accidents is far more than that of HIV infection every year.
(2) Skin damage: Long-term contact between damaged skin (small wounds, ulcers, abrasions, etc. ) and whole blood, serum or plasma with HBV or AIDS virus can cause infection.
(3) Mucosa: Blood spatter caused by the unclosed test tube and centrifugal accident, and whole blood, serum or plasma containing HBV or AIDS virus contacting the oral cavity, nasal mucosa or conjunctiva can all cause infection.
Literature shows that HBV can be infected when skin or mucous membrane comes into contact with objects (such as telephone, test tube, instrument surface, etc.). ) contaminated with HBV blood. So far, there is no report that HIV can be transmitted through this indirect contact. The hands of medical staff are most easily contaminated by HBV, such as biting nails, smoking, eating, arranging contact lenses, etc. Mouth, hands? Eyes, hands? Nasal contact can constitute indirect contact.
Second, the protective measures in hematology test. Medical staff are all high-risk groups infected with HBV and other viruses. The Centers for Disease Control (CDC), Occupational Safety and Health Administration (OSHA) and National Committee for Clinical Laboratory Standards (NCCLS) all issued relevant documents and formulated corresponding protective measures. When implementing these measures, we must first make it clear that because the virus infectivity of a blood sample is unknown, we must assume that all blood samples are infectious in our work, strictly implement protective measures, and we must not take chances.
1. Use hematology laboratory supplies with excellent safety: Pursuing safety and protecting the health of medical staff and patients are the trends in the design and production of hematology laboratory supplies in recent years. At present, major medical device companies have introduced blood sampling inspection products with excellent safety. Some advanced countries in Europe and America generally adopt safety-leading products in inspection to improve the quality of working environment. Taking blood collection equipment as an example, our hospital has used vacuum blood collection system, which greatly reduces the possibility of direct or indirect contact between medical staff and blood samples in blood collection, specimen transportation, treatment and waste disposal.
2. Wash your hands: After touching patients and blood samples, washing your hands frequently is an important and effective self-protection measure. Routine hand washing, washing with soap and tap water is enough, no disinfectant is needed. Disinfecting paper towels are not recommended. Use disinfectant paper towels instead of water, which can't fully dilute or wash off the pollutants on your hands. Wash your hands often. You can wear some skin care products to protect your skin after washing your hands. It is recommended to wash your hands in the following situations: (1) When your hands are stained with blood visible to the naked eye. (2) After the work is completed. (3) After taking off gloves. (4) Before eating, smoking, putting on makeup, changing contact lenses and going to the toilet. (5) Before the hand comes into contact with mucosa, eyes or broken skin.
3. Wear gloves: Wearing medical latex gloves can provide good protection for medical staff. Although latex gloves can't avoid the mechanical damage caused by needles, they can greatly reduce the contact between skin and blood. Moreover, when the needle causes accidental injury, latex gloves can also play a role in blocking and sealing, reducing the amount of blood entering the wound, thus reducing the possibility of infection. It is suggested that blood collectors must wear gloves in the following situations: (1) When the skin of blood collectors' hands is damaged. (2) When uncooperative patients draw blood. (3) When blood is collected by skin puncture (for example, when finger blood is collected). (4) When training new blood collectors (it can not only protect students but also make students get used to wearing gloves to collect blood).
4. Removing blood: The vacuum blood collection system is a fully enclosed system, which can effectively reduce the chance of blood splashing in the process of collection, specimen transportation and specimen processing. However, various operational accidents may also occur, resulting in environmental pollution of blood samples. If the traditional syringe test tube is used to collect blood, the test tube has no cover and the system is open, the chance of blood sample polluting the environment during hematology examination will be greatly increased. No matter which system is adopted, once the blood sample is contaminated, medical disinfectants should be used to remove the blood stains.
The specific removal steps are as follows:
(1) Wear thick latex gloves and protective clothing if possible before cleaning. If there is broken glass or other benefits in the blood, it should be swept away first, and it must not be touched by hand. If there is too much blood, you can consider wearing waterproof rubber shoes.
(2) Use toilet paper, gauze or paper towels to suck blood to increase the efficacy of disinfectants.
(3) Clean the contaminated surface and blot it dry.
(4) Disinfect the surface with medium and high efficiency medical disinfectant. Disinfectants should be kept for enough time.
(5) Disinfectant can be sucked dry or allowed to dry by itself.
(6) Wash the surface with water and dry it to prevent slipping.
(7) Put all wastes into special containers and discard them in accordance with the relevant regulations of the hospital.
5. Use and disposal of needles: Needle injury is the most important cause of occupational HBV and HIV infection, so be extra careful when using needles. In the process of operation, in principle, we should use needles as little as possible and reduce the operation of needles. It is recommended to use a vacuum blood collection system. Most vacuum blood collection system manufacturers provide special needle handling containers. After taking blood, the blood sample is already in the vacuum tube. Holding the needle holder in one hand can easily take the needle out of the groove of the special needle handling container, and the needle automatically falls into the solid container. In this way, the quality of blood samples and the safety of personnel are well protected.
Third, the unexpected handling of hematology tests Medical personnel should immediately wash the skin with needle injury or blood in the process of operation, and then wash the wound or pollute the surface with a lot of water. Bandage the wound if necessary. Mucosa or conjunctiva should be washed with plenty of water after being contaminated by blood.
1. Accidental contact with HBV: HBV can be transmitted through direct or indirect accidental contact. Patients can infect medical staff, and medical staff can also infect patients. It is suggested that all medical workers who may be exposed to HBV must be injected with hepatitis B vaccine.
2. Accidental contact with HIV: HIV can be transmitted through direct accidental contact, and there is no report of indirect accidental contact. HIV can be transmitted from patients to medical staff, and also from medical staff to patients. Because there is no effective AIDS vaccine, it is impossible to prevent immunization after accidental contact with HIV. CDC has issued a prevention plan using azido-dideoxythymine (AZT). AZT is the first anti-HIV drug approved by the US Food and Drug Administration (FDA), and its mechanism is to prevent the reverse transcription of viral RNA into DNA. The prevention scheme based on AZT has certain effect, but the curative effect is still uncertain and still in the experimental stage.
If the blood sample accidentally contacted is confirmed to be HIV positive or extremely suspected to be positive, this prevention scheme can be considered. If you decide to use this prevention plan after direct accidental contact with HIV, you should implement it as soon as possible.
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